Engine having diametrically opposed cylinders



1939' A. J. STUBINGS v 2,170,099

ENGINE HAVING DIAMETRIGALLY OPPCSED CYLINDERS Filed NOV. 30, 1937Patented Aug. 1939 UNITED STATES PATIENT OFFICE Alfred James Stubings,Richmond, England, as-

signor to Tllling-Stevens Limited, Maidstone, Kent, England, a Britishcompany Application November 30, 1937, Serial No. 177,391 InGreatBritain December 15, 1936 invention relates to.engines having oneor more pairs of diametrically opposed cylinders,

and more particularly to the coupling of the two opposed pistons to thecrank pin of the'crank- 5 shaft of' internal combustion engines.

Hitherto three different methods have been employed for this purpose,viz:

1. Eachpiston of the pair was attached to a connecting rod of which one,the master conm necting rod, is journaled at its big end on the crankpin in the usual way, whilst the correspending end (thearticulatedend)of the other connecting rod was pivotally secured to the big end of themaster cohnecting rod by a wrisfpin.

l5 This'construction. had the disadvantage that owing to the ellipticalpath ofmovement of the articulated end. of 'the'latter connecting rod,

forces were setup which were not easy to balance. Also the load imposedon the crank pin The disadvantage here lay. in the fact that the forkmade for a weak construction of connecting rod bigenda f 3. The big endsof the two connecting rods were mounted side by side on a common axis,namely the crank pin, the axes of the two. cylinders of each pair beingoff-set or staggered to the necessary amount.

The undesirable feature of this construction was that the overall lengthof the engine was increased, particularly if there-were several pairs ofcylinders; moreover this side-by-side arrangement of the connecting rodson the crank pin gave rise to a "couple" at this point. The object ofthis invention is to provide a construction possessing all theadvantages of the constructions enumerated above and yet avoiding allthe undesirable features mentioned, and\) generallyto provide an engineof compact di-i mensions which will beeflicient in use. According tothis invention there is provided,

in or-for an engine of the type described, the 1 1 construction whereinthe? two opposed pistons are coupledv together and drive the crank pinby a single, connecting rod attached 'toone of said pistons."

' The invention moreover embraces, in or for. an

internal combustion engine, a rigid connection between the two opposedpistons and .asingle at its smallend 2 Claims. (01. 123-56) connectingrodfor coupling the pistons to the crank pin.

According to a further feature ofthe invention each piston is relativelyshort in the skirt and is guided and supported in its movement by a 5.member rlgidiyattached thereto, and deriving its support from' a pointremote from the piston. 'According to yet another feature. oftheinvention, the piston of one cylinder acts as a guide and support forthe piston in the opposing l0 cylinder through the medium of the memberwhich rigidly connects the two pistons together. 3 One embodiment ofthis invention will now be described, merely by way of example, withreference to the accompanying drawing, .as applied to an internalcombustion engine having, say, four pairs of horizontally, opposedcylinders. The

'number of pairs 'of cylinders being immaterial so far as the inventionis concerned, the followingdescription is directed to the constructionrelatgo ingto any one pair ofopposed cylinders and pistons.

In the accompanying drawing--- 7 Figs 1 is a transverse sectionalelevation of the engine. r

Fig. 2 is a sectional plan taken in the line :c--:: of Fig. 1, lookingin the direction of the arrows.

-Fig. 3 is a side elevationof the pair of opposed. pistons with theconnecting plates attached, and ,0

Fig. 4 is a plan of Fig. 3. Referring to the drawing, the axes of thetwo" cylinders 2 are in alignment and the pistons i, 3 in. these twocylinders. are; in accordance with the invention, rigidly interconnectedby two 35 spaced connecting latest.

v Each connectin plate 4 is of identical construction andcomprises acentral ring-shaped portion 4' having diametrically opposite extensionsl (Fig. 3) "provided with flat portions 5 40 adapted to be bolted bybolts 6 to'co'rresponding flat surfaces machined on the pistons 3, 3!.These surfaces on the .pistonsare adjacent'the point, wherethe usualgudgeon pin bosses are to be found. a

The connecting plate .4 is shown in the drawingto be of flat section,but it may be composed of members of any desired section, either whollyor partly solid, hollow or of angle section, with or .without webs,fillets, braeings or other reinforceme'nts' 9 The piston 3 is coupled"by: means of a single connecting rod 1 to the crankshaft 8, the smallend I being secured to the piston I by ag'udgeon pin 9 and the big end lbeing journaled on the crank pin l0, both in the normal manner,

In this way both pistons 3, 3 'are coupled to the crankshaft 8 and thedifiiculties arising out of the. use of two connecting rods involvingtwo bearings in the vicinity of the crank pin are thus overcome.

The two connecting plates 4 are spaced apart so as to lie one oneachside of the connecting rod I and between the planes defined by theconfronting surfaces of the crank pin supporting vWebs oi.

the crank shaft and the purpose of the central ring-shaped portions 4 isto afiord clearance for the crank pin Ill and the big end I of the rod1.

In an engine of orthodox pattern, the length of the piston skirt must besufficient to provide an adequate guide in the cylinder, but animportant advantage arises from the present invention in that theoverall width of the engine may be materially decreased by cutting downthe length of the piston skirt. This may be done because the rigidconnection between the two pistons 3, El causes one piston to act as a'guide and support for the other piston in a manner similar to across-head.

Consequently extremely short pistons can be employed with amaterial'saving in weight and overall width of the engine.

What I claim is- 1. In an engine having a pair of diametrically opposedcylinders, a crank-shaft journalled between said cylinders, said'crank-shaft including spaced web members ,supporting a crank-pintherebetween, opposed pistons operating in said cylinders and aconnecting rod coupling one of said pistons to the crank-pin; rigidconnecting means between said pistons comprising two spaced connectingplate members the I extremities of which are fixedly secured to therespective pistons, said plates disposed on opposite sides of theconnecting rod and between the planes defined by the confronting innersurfaces of the crank-pin supporting web portions of the crank-shaft,each of said plates having a centrally disposed ring shaped portiondefining an opening of suflicient size to accommodate the movement ofthe crankpin and the bearing portion of the connecting rod securedthereto.

I 2. In an engine having a pair of diametrically opposed cylinders, acrank-shaft journalled intermediate said cylinders having spaced webmembers forming the crank portion thereof which web members support acrank-pin therebetween and have portions projecting beyond said shaftopposite said crank-pin, opposed pistons operating in said cylinders anda connecting rod coupling one of said pistons to said crank-pin; rigidconnecting means between' said pistons comprising two spacedsubstantially parallel plate members rigid 1y connected at theirextremities to the respective pistons, said plates being disposedon-oppo-' site sides of said connecting rod and between the

